1. Field of the Invention
The present invention relates to an apparatus and method for supplying powder quantitatively and a material supplying apparatus including the apparatus for supplying powder quantitatively.
2. Description of the Related Art
Plastic goods having a desired color or special function can be produced by using additives having the desired color or special function in plastic materials (e.g., LDPE, EVA, PP, PET, PC, PVC, etc.) while molding the plastic materials using a process of extrusion or injection.
However, since additives are mostly powder or liquid, it is technically difficult to uniformly mix them with the plastic materials and thus the plastic materials have a different distribution density, making the color of the plastic goods bridged or spotted. Therefore, it is very difficult to produce plastic goods having the desired color or special function.
To uniformly mix powder with the plastic materials, the plastic materials are previously coated with a required amount of powder, the powder and the plastic materials are fused by melting them together, or concentrated powder is provided to the plastic materials using a carrier, etc. However, since it is necessary to separately measure or transfer the powder, the plastic goods have a very low productivity, and the measured amount of powder is different from the used amount of powder, causing the plastic goods to be of low quality.
To solve the problem of the conventional methods, a gravimetric quantitative feeding method using a microbalance or a volumetric quantitative feeding method using a micro-screw have been suggested. However, since these two methods cannot prevent the powder from bridging, generating static electricity, and flying into air due to the measurement or transfer of the powder, it is difficult to supply powder quantitatively.